The present invention relates to bow presses for maintenance of compound archery bows.
A typical compound archery bow includes a pulley at one end and an eccentric cam at the opposite end around which the cable of the bowstring is passed. The stringing or tuning of a compound bow, with its eccentrically mounted cam and its pulley, tension cable and bow string, is critical to achieve a proper balance of the eccentrically mounted pulleys or cams. The complexity of the stringing and the sensitivity to proper tuning of the bow, makes it very difficult to string and tune a compound bow without the aid of a bow press.
Periodic retuning of compound bows is often required to maintain desired performance levels. For retuning and to change, replace or repair components of the compound bow, such as the bowstring, string sights, dampers, the tension cable, the cams and other components, a bow press is required.
Through the years a number of bow presses have been developed for facilitating stringing and maintenance of compound bows. In general, these presses have included a stationary base having a pair of spaced apart inside surface supports, in the form of pegs or rollers, for contacting the inside of the bow, and a pair of limb supports, in the form of pegs or rollers, attached to a movable mechanism for applying a bending force to the limbs of the bow. Such a bow press is described in Gibbs, U.S. Pat. No. 6,968,824.
It is very important that the inside surface support and the limb supports of the bow press be precisely positioned in such a manner that the bow is properly loaded into the press in a manner that when the limbs are bent, the forces will not overstress or otherwise damage the bow. Because compound bows vary dimensionally, particularly in riser length, it is necessary that the inside surface support and the limb supports on the bow press be adjustable. In the past, it has been customary to provide incremental holes in the bow press so that the position of the inside surface support and the limb supports could be moved to achieve a satisfactory fit with regard to a given bow. The incremental nature of this adjustment approach often results in a fit of the bow press to the bow which is not quite ideal, and can result in damage to the bow. In the patent to Gibbs, U.S. Pat. No. 6,968,834, an improvement is made to allow manually adjustable sliding clamps which are selectively moveable along a beam and when located properly, may be clamped to the beam by tightening bolts or set screws.
As archery technology has progressed, compound bows have been developed which include much shorter limbs than earlier compound bows, with the short limbs designed to join the bow riser at a substantial angle approaching a perpendicular, and hence the limbs sweep back toward the user. These swept back limb bows are frequently termed “parallel” limb bows or “short limb” bows. Pressing of such bows in the prior art bow presses has proved to be challenging.
Certain deficiencies in the bow press disclosed in Gibbs, U.S. Pat. No. 6,968,834 have been identified, especially when such, a bow press is used with short limb bows. First, the adjustability of the link members which connect the pivot arms to the jack is challenging to accomplish by a lone user because the user must employ one hand to lift one pivot arm so that the limb engaging member abuts the limb while at the same time attaching the link member to the jack and when the link member to attached is the second, matching the link member's effective length to the other link member. Then, if a user forgets to place the spring clip to retain the link members to the jack, the link members may slide off the pin on the jack when compression is applied to the bow, causing a potentially injurious condition.
Additionally, with a bow press such as disclosed in Gibbs, U.S. Pat. No. 6,968,834, retention of the limb deflecting brackets along the pivot arms by friction, through use of a set screw, requires excessive effort to adequately secure the bracket in place along the pivot arm.
A conventional bow press must be adjusted each time the press is to be used, to adjust the press for the particular bow to be pressed, until the adjustable elements of the press are matched to the particular bow. This is usually accomplished through time consuming experimentation.
Finally, when pressing a parallel or other short limb bow with a conventional bow press, it is possible to compress the limbs toward one another to the point where the bow may spring out of the bow press, escaping containment and creating a dangerous condition.
These safety and efficiency deficiencies deserve remediation.
It is desirable, therefore, to provide an improved bow press apparatus which overcomes problems and shortcomings of prior art bow presses, and allows safe compression of a short limb bow.